I/O 55 error

[mikecruz]

We have a 2015 Quick Turn Universal 250M with a Mazatrol Smart control. For the last few years, we have been struggling with a persistent I/O 55 error during tool changes. Mazak service has been unable to fix this, as well as an outside Mazak service company has been unsuccessful. Mazak's only recourse is to try to sell us a replacement machine, but since we feel it is not that old and still runs 75% of the time without a problem, we would rather still try to fix the problem. We feel it may be temperature related, but we have done everything, even pumping cool air into the main electrical box on the machine, to no avail. Anyone else have this same issue and a fix? Any thoughts on this would be appreciated. Thank you.

 

[cnctoolcat]

If you're only seeing the alarm when the turret is indexing, that helps to narrow the problem down.

It sounds like a communication issue between the cnc control and the turret motor vfd.

If not a bad cable, the vfd itself could be failing, or the turret motor or encoder. I would bet it's the Mitsubishi vfd going bad, so I would replace that first. Then a new motor and encoder and possibly cabling. Will cost several grand, but still better than buying a new machine!

Call Mitsubishi (MEAU) in Chicago or New Jersey; they build all the electronics on a Mazak, and the right tech there might can help.

Good luck with it, keep us posted.

ToolCat

 

[noname777]

That is one of your I/O extension boards playing up. There is a way to find which one is faulty and swap them or replace. I have a written way how to do it. wait a sec, need to find it. It is a bit complicated than basic troubleshooting, no wonder people find it hard to fix. I think we already discussed it here, probably 3 years ago.

 

[noname777]

Ok. So that is the general idea and with examples taken from Mazak Vertical Center ( SMART).
first of all we need this Alarm 55 IO with the number that is attached to it, as it says what station and system are "suspected" to be faulty. That is the funny part of it. Your machine have systems and stations for Remote IO boards. Once system is configured, stations are connected in a chain. If one station is troublemaker ( say, somewhere in the middle of the chain) than all other station are not visible to NC. Sometimes you can get error pointing to one particular station , while in reality the faulty one is connected before this one.

Here are pictures form Smart mill where you can see what systems are and stations as well. Also a screenshot of DIAGNOSTIC monitor to check status of diagnostic registers R5xxx. You need to do the same and see if you have any numbers growing really really big.

You can see the page where all diagnostic registers are listed and also this info:
SIGNAL NAME:
-max value of communication ( probably , how many times NC lost communication with this particular IO board and have managed to reestablish it later)
-Max value CRC ( that is redundancy code to check if any data was lost during communication phase )

Accumulated values are the same but since the machine creating.

If you see any numbers mad big or whatever, you can probably swap remote IO boards ( don't forget to change rotary switch address) and see if problem moves.

if it moves , you will see the same error 55 IO remote , but with different number attached to it, pointing to different location ( physical location ).

That is the only way to troubleshoot the problem, unless you have someone from Mitsubishi and he has some other " classified " information, not available to other mortals.


P.S in my example, we have system 1 and 3 with 3 stations attached. And as you can see, R5xxx registers correspond to my configurations. So I assume, that this applicable across all Mazaks.

 

[noname777]

Here is proper explanation how it works, thanks to Mitsubishi. Haha.
These are PLC - NC interface signals to indicate that something isnt right with Remote IO. That shows you the way Mits are running their own diagnostics.